"You don't get it, do you?

You don't build the rocket at sea level and truck it up there. You build a rocket assembly plant at altitude. Remember that (one of) the chief weakness(es) of the space shuttles was the remote fabrication of the boosters and their shipping in subunits before final assembly on site.

I realise there are major issues with oxygen availabiliy near the summit, but these issues are tractable given either a selection of Peruvian and Tibetan employees or supply of oxygen on-site or a lower-latitude assembly site with a dedicated constant grade incline to raise the assembled rocket up - like the Apollo crawler, but uphill.

Of course, there would then be a large town perched high on the flanks of the peaks of Hawai'i.

The point is, this is no more absurd than your pipelauncher."

Well, I would built a pipelauncher in a shipyard and therefore for construction you don't need to import as you say Peruvian and Tibetan employees to some location.

But ok, I get that you are being absurd. I guess I was wrong not to see the sarcasm and took it as something that was somewhat serious. But I must say, it's difficult to detect sarcasm in this typed communication.

"Any added component to a launch system MUST offer sufficent advanges to offset the disadvantages of another "stage" which has to be timed in synchronicity with others and has its own failure paths.

I am far from convinced that the sub-1% advantages of a spring loaded launch system (which is what your pipelauncher is) is worth the added complexity and failure routes."

The way I look at it is that a pipelauncher would probably be as hard to operate as a bicycle, and until it's tried people will have doubts about whether it's ridable.
And yes, I'm sure the suits in general will think it's not worth the risk. And yes there will actually be real risks associated with accelerating a rocket 1/2 gee or more- after all the rockets were not designed with this in mind and even if the were designed with this in mind there is still a possibility that any time you do any new something would go wrong.
But to your point precisely, the value of pipelauncher in near term is as a launch pad, rather than how fast it get the rocket moving. If fear is overriding concern perhaps you design it for 1 gee acceleration but only launch at 1/4 gee or less, until such time that one has less fear.

"Note also that the entire launch system will have to be marinised. For Zenit and Sea Lunch - they are reusing an existing (small) lunch system which has ALREADY been marinised for its original esign as a sea-launched ICBM.

Now try doing that with an Ares-scale launch system..."

Well if the Ares is being launched from KSC it better be designed to withstand some marine conditions because it will be launched near the ocean.

And with a pipelauncher, no part of the rocket should normally get any closer then 10-20' from any ocean water.
And if for whatever reason you needed to park a rocket on a pipelauncher for an extended period [days- weeks] you could have it parked a hundred or two hundred feet above the water- thereby probably exposing it to less marine conditions than if parked on a pad at KSC for same period.

Also I don't know where you got idea that Zenit was orginally designed as sea launched ICBM. First, is too big for a ICBM- a ICBM is a sub-orbital vehicle. ICBMs which have been modified for orbital payload can generally put a ton or two into LEO. A Zenit-2 can put 13.74 tonne to LEO and a Zenit-3SL [the one used by Sea Launch] puts about 6 tonne to GTO- according to:
http://www.answers.com/topic/zenit-rocket
And according to above:
"Zenit was built in the 1980s for two purposes: as a liquid rocket booster for the Energia rocket and, equipped with a second stage, as a stand-alone rocket. Moreover Zenit was planned to take over manned spaceship launches from Soyuz, but these plans were abandoned after the fall of the Soviet Union."
The Zenit-3SL is a fairly big rocket, there are bigger rockets such a Ariane V, Altas V, Delta IV heavy, or Russian Proton.